Autism rate jumps to 1 in 88 kids in CDC study

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Mar 30, 2012 at 12:01 AMMar 30, 2012 at 11:32 AM

LOS ANGELES - Federal health authorities have significantly raised their estimate of the prevalence of autism in children, concluding in a new study of 8-year-olds that 1 in 88 has some form of the disorder.

LOS ANGELES - Federal health authorities have significantly raised their estimate of the prevalence of autism in children, concluding in a new study of 8-year-olds that 1 in 88 has some form of the disorder.

The analysis, based on a review of tens of thousands of health and school records in 14 states, was released yesterday by the U.S. Centers for Disease Control and Prevention. It is the latest in a series of studies showing autism rates climbing dramatically over the past decade. The previous estimate of the incidence of autism was 1 in 110.

Although the new numbers are sure to fuel debate over whether a growing environmental threat is at work, researchers said the data suggest that rising awareness, better detection and improved access to services can explain much of the increase.

Dr. Daniel Geschwind, an autism expert at UCLA, said he was initially surprised by the size of the increase - 25 percent in two years. "But when I looked at what seems to be driving it, it made total sense," he said.

Geschwind and others said vast differences in the rates among states included in the study are almost certainly a reflection of social and cultural factors that influence who gets a diagnosis.

Nobody knows what causes autism, and there is no blood test, brain scan or other test that can point to a biological marker. It is diagnosed by its symptoms: social and communication difficulties starting in early childhood, repetitive behaviors or abnormally intense interests.

Autism rates have exploded since the 1990s as the definition expanded to include milder cases, efforts to identify the disorder intensified and publicly funded services became widely available.

In response to rising concern, the CDC set up a series of surveillance sites across the country. Researchers periodically scour health and special-education records of hundreds of thousands of 8-year-olds for the signs of autism or a diagnosis.

In its first analysis, using data from 2000, it estimated that 1 in 150 children had some form of the disorder. By 2006, it was 1 in 110.

The latest estimate of 1 in 88, based on 2008 data, is already being touted as evidence that autism is an epidemic and that something in the environment is driving it.

Mark Roithmayr, president of the advocacy group Autism Speaks, called for more government funding for research and treatment.

"Inevitably, when these statistics come out, the question is, what is driving the increase?" said Roithmayr. Better diagnoses, broader diagnostic criteria and higher awareness account for about half the rise, he estimated.

The CDC identified 3,820 children as having autism among 337,093 children in its surveillance area.

In boys, the rate of autism-spectrum disorders is one in 54, almost five times that among girls - one in 252.

Although the overall rate was 1 in 88, it varied considerably among the 14 sites, from 1 in 47 in Utah to 1 in 208 in Alabama.

The rates also varied by race: 1 in 127 among Latinos, 1 in 98 among blacks and 1 in 83 among whites.

The latest numbers, however, show the geographic and racial gaps narrowing.

Prevalence studies that rely on records are inherently limited, said Kim, the Yale autism expert.

In a study published last year, her research team attempted to screen all 55,000 children in a suburb of Seoul, South Korea, and found that 1 in 38 met the current definition for some form of autism.

Two-thirds had never been identified with autism or any other disability. Had the researchers used the CDC methodology, Kim said, they would have missed all those cases.

She briefly considered titling her paper, "Seek and You Shall Find."

Kim and many other researchers see the boom in diagnosis as a positive step, a chance to bring help to children who would have been missed in the past.

But the study also suggested to some researchers that the definition left too much room for interpretation.

In February, the American Psychiatric Association proposed criteria for autism that would eliminate both Asperger's and a condition known as "pervasive developmental disorder, not otherwise specified," as separate diagnoses in the coming revision of the Diagnostic and Statistical Manual of Mental Disorders. All would be placed under one category of autism-spectrum disorder, with different levels of severity.

Some researchers think the changes might narrow the criteria enough to curb the rising tide of autism diagnoses, although others disagree.

The psychiatric association says its only goal is to meet the need for clearer criteria, so that diagnoses are more consistent and more accurate in schools, clinics and centers throughout the country. That, in turn, will lead to better treatment, said Dr. James Scully, the association's medical director.

Information from Dispatch archives and Reuters was included in this article.